Born in circa 1824 to Tuʻi HaʻapaiTāufaʻāhau and one of his secondary wives, Kalolaine Fusimatalili, of the Fusitua line. His father Tāufaʻāhau later became King George Tupou I of a united Tonga. On 7 August 1831, Tupou was baptised into the Christian faith along with ʻUnga and his sibling. He was given the name Tēvita or David after the biblical King David. Following Tupou's marriage to Sālote Lupepauʻu in the Christian rite, he cast aside his secondary consorts and declared all his children by them illegitimate including ʻUnga. After his father moved to Tongatapu, he appointed ʻUnga as acting governor of Vavaʻu. In July 1865, English explorer Julius Brenchley visited Vavaʻu for five days and met governor ʻUnga, who he described:
The governor is a very tall, imposing-looking man, in spite of the loss of an eye, the result either of an accident or a wound in war. He was also minus two fingers, cut off as a tribute, according to the custom of these islands, to some deceased relatives. David has the reputation of being a great warrior, and a friend of civilization; he speaks a little English, provided there be no missionary within earshot. I found him dressed in a piece of tapa, which he told me he changed every three days, and which covered all his body with the exception of his legs and feet. He has a bed and some old furniture of European make; his flag, the same as his father's, is red, with a cross of the same colour on a white ground in the upper corner.
After the death of Queen Sālote Lupepauʻu's son Prince Vuna Takitakimālohi in 1862, Tupou I was left without an heir to the throne. As a result, ʻUnga was legitimised and named Crown Prince under the terms of the first written constitution of Tonga on 4 November 1875. ʻUnga was appointed the first Prime Minister of Tonga on 1 January 1876, a post he held until his death. In November 1879, Reverend Shirley Waldemar Baker accompanied ʻUnga to Auckland for medical treatment. The Prince had been suffering from a serious liver ailment. The treatment was unable to save the Prince and he died in Auckland on 18 December 1879. Through the influence of Reverend Baker, the Crown Prince's remains were brought back on the German warship Nautilus on 20 May 1880. The funeral on 10 June at ʻUiha, Haʻapai was attended by the German marines aboard and gun salutes from the Nautilus added much pomp and grandeur to the event. As a sign of his gratitude, King Tupou I appointed Reverend Baker the next Prime Minister of Tonga. His father Tupou I would outlive ʻUnga's three children and be succeeded by his great-grandson George Tupou II, ʻUnga's maternal grandson.
Marriage and issue
His first wife was Fifita Vavaʻu, second daughter of Liufau, Tuʻi Haʻangana Ngata, by his second wife, Hulita Tuʻifua. From his first marriage, he had three children:
Crown Prince ʻUiliamu ʻUelingatoni Ngū Tupoumālohi, served as Governor of Haʻapai and Vavaʻu from 1877 to 1885. He inherited the title of Crown Prince on his father's death. He married Asupa Funaki, daughter of Babanga Moala. He had no children with his wife, but had three illegitimate children, two sons and one daughter.
Crown Prince Nalesoni Laifone, he was Crown Prince from 1885 until his death in 1889. Married Luseane Angaʻaefonu, eldest daughter of The Hon ʻInoke Fotu and Princess Lavinia Veiongo Mahanga, daughter of Laufilitonga, the 39th and last Tuʻi Tonga. This marriage produced no children, but he left two illegitimate daughters.
His second wife was Teisa Palu, daughter of Maheʻuliʻuli, 1st Fangupo, and his wife Levave. They had no children.
